Sideritis chamaedryfolia

Source Sideritis chamaedryfolia Cav. Mol, formula C2qH2 02 Mol. wt. 306 Solvent CDCU... 

Some years later, S. chamaedryfolia was reinvestigated and the structures of some minor products were elucidated four known ent-kauranes siderol (34), epicandicandiol (7), 7-acetyl-epicandicandiol (8), isofoliol (36) and seven new labdane derivatives villenol (110), 19-acetyl-villenol (111), villenolone (112), 19-acetyl-villenolone (113), villenatriolone (114), villenatriol (115), 19-acetyl-villenatriol (116). It is very interesting that these seven products have the (rare in Sideritis) normal configuration [52], One year later, a re-examination [53] of this species led to the isolation of a new derivative, ent-11 (3,18-dihydroxy-kaur-15-ene (49). 

Sideritis (Labiatae) species have continued to attract attention as a source of diterpenoids. n/-lljS,18-Dihydroxykaur-15-ene (49) was obtained from 5. chamaedryfolia and the known diterpenoids foliol (enr-3/8,7a,18-trihydroxy-kaur-16-ene) and its 3- and 18-monoacetates (sidol and linearol) were detected in S. arborescens ° and along with their A -isomers and 18-hydroxykaur-16-ene (candol B) in S. flavovirens. A similar group of hydroxykaurenes was found in S.funkiana whilst enr-18-acetoxy-3jS,6a,7a-trihydroxykaur-15-ene (funkiol) and the isomeric 3-acetate (sidofunkiol) were amongst the minor constituents. The selective allylic oxidation of the kaur-16-enes at C-15 by hydrogen peroxide and selenium dioxide is facilitated by the presence of a 7-hydroxy-group. 

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